83139781 has 8 divisors (see below), whose sum is σ = 86526720. Its totient is φ = 79787568.

The previous prime is 83139743. The next prime is 83139811. The reversal of 83139781 is 18793138.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 83139781 - 2¹³ = 83131589 is a prime.

It is a super-2 number, since 2×83139781² = 13824446369455922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (83139701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3741 + ... + 13426.

It is an arithmetic number, because the mean of its divisors is an integer number (10815840).

Almost surely, 2^83139781 is an apocalyptic number.

It is an amenable number.

83139781 is a deficient number, since it is larger than the sum of its proper divisors (3386939).

83139781 is a wasteful number, since it uses less digits than its factorization.

83139781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17363.

The product of its digits is 36288, while the sum is 40.

The square root of 83139781 is about 9118.1018309734. The cubic root of 83139781 is about 436.4518031431.

The spelling of 83139781 in words is "eighty-three million, one hundred thirty-nine thousand, seven hundred eighty-one".